title: Single particle detection, manipulation and analysis with resonant optical trapping in photonic crystals.
abstract: We demonstrate a resonant optical trapping mechanism based on two-dimensional hollow photonic crystal cavities. This approach benefits simultaneously from the resonant nature and unprecedented field overlap with the trapped specimen. The photonic crystal structures are implemented in a 30 mm × 12 mm optofluidic chip consisting of a patterned silicon substrate and an ultrathin microfluidic membrane for particle injection and control. Firstly, we demonstrate permanent trapping of single 250 and 500 nm-sized particles with sub-mW powers. Secondly, the particle induces a large resonance shift of the cavity mode amounting up to several linewidths. This shift is exploited to detect the presence of a particle within the trap and to retrieve information on the trapped particle. The individual addressability of multiple cavities on a single photonic crystal device is also demonstrated.
authors.affiliation: Institut de Physique de la Matière Condensée, École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Descharmes
authors.forename: Ulagalandha Perumal
authors.initials: UP
authors.lastname: Dharanipathy
authors.forename: Zhaolu
authors.initials: Z
authors.lastname: Diao
authors.forename: Mario
authors.initials: M
authors.lastname: Tonin
authors.forename: Romuald
authors.initials: R
authors.lastname: Houdré
mesh_terms: D017097:Electric Impedance; D055620:Optical Phenomena; D052898:Optical Tweezers; D010316:Particle Size; D017785:Photons